Domain Access on Platform.sh

gistfile1.php

/**
 * Implements hook_domain_default_domains().
 */
function MYMODULE_domain_default_domains() {
  $domains = array();
  $domains['wipe-domain-tables'] = 'wipe-domain-tables';

  $routes = (array) json_decode(base64_decode(getenv('PLATFORM_ROUTES')));

  if (!empty($routes) && is_array($routes)) {
    $weight = -1;
    foreach ($routes as $url => $route) {
      if (
        $route->upstream == 'drupal'
        && preg_match('/^(https?):\/\/([a-z0-9\.-]+)\/$/', $url, $matches)
        && preg_match('/^https?:\/\/([a-z]+).{default}\/$/', $route->original_url, $matches2)
      ) {
        $scheme = $matches[1];
        $domain_name = $matches[2];
        $machine_name = $matches2[1];

        $domains[$machine_name] = array(
          'subdomain' => $domain_name,
          'sitename' => MYMODULE_get_sitename($machine_name),
          'scheme' => $scheme,
          'valid' => 1,
          'weight' => $weight++,
          'is_default' => ($machine_name == 'www' ? 1 : 0),
          'machine_name' => $machine_name,
        );
      }
    }
  }

  return $domains;
}